Felipe cоntrаcts with Minnetоnkа Dоzers, LLC (Minnetonkа) to raze his old building for $12,000. Once Minnetonka begins the work, its employees discover asbestos in the building. Asbestos is hazardous and difficult to remove for environmental and safety reasons, and this will result in an additional $15,000 labor expense. Minnetonka refuses to complete the job until Felipe agrees to pay the additional $15,000. Felipe agrees. Is the contract modification enforceable?